Typical semiconductor processing equipment such as plasma-etching equipment is provided with a temperature control device for controlling the temperature of a chamber. Specifically, a pump-discharge flow rate of a temperature-adjusted circulating fluid is measured in advance using a flowmeter, and the temperature control device performs a feedback control based on the measurement result to adjust the pump-discharge flow rate to a flow rate setpoint, thereby maintaining the temperature of the chamber at a temperature setpoint. Thus, the temperature control device includes a circulating cooling/heating device configured to cool/heat the circulating fluid, which is circulated between the temperature control device and the chamber by a pump after being temperature-adjusted, and measure the flow rate of the circulating fluid.
The temperature of the circulating fluid, which is typically set at approximately 90 degrees C., has recently been demanded to be set higher. However, such a high-temperature circulating fluid may thermally affect a typical flowmeter with a revolving part such as a rotor, lowering the mechanical reliability of the flowmeter. In view of the above, a high-temperature resistant flowmeter is favorably usable. However, such a flowmeter is costly because it is structurally complicated and made of a special material to reduce a thermal influence on it.
It is widely known that the flow rate of the circulating fluid supplied to the chamber interrelates with the fluid pressure of the circulating fluid flowing in a flow path (see, for instance, Patent Literature 1). Thus, a pressure sensor, which is structurally simple and unlikely to be thermally affected, may be used instead of a flowmeter to maintain the pressure of the circulating fluid at a pressure setpoint based on the detected pressure of the circulating fluid or to adjust the flow rate of the circulating fluid to a flow rate setpoint based on a flow rate calculated from the detected pressure. This technique eliminates the necessity of a costly flowmeter, and thus reduces the component costs of the circulating cooling/heating device.